Looks more lightweight now, but still it's 12k LOC vs 1k LOC in Backbone. Need to look through, what do those 11k offer :)

Pure JS and drop-in integration is good too, we are a Java shop and lots of developers working on Windows, so introducing a Ruby-dependent JS framework would be hard in my case.

Previously we also considered SC as a 'heavy' JS solution - like Cappuccino, ExtJS or GWT(we used GWT for complex backends - it allowed us to share UI&server code), but now we'll have another look at it as an alternative to Backbone for frontends/mobile.